ArrayList OutOfBounds-Java（Android）编程

LogCat输出的错误指向QuestionView.java的第37行，我将在下面的代码中对其进行注释。下面我有4个类的4个片段。我还有LogCat的输出

MainMenu.java

public class MainMenu extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainmenumain);

    Button button1 = (Button)findViewById(R.id.startBtn);
    Button button2 = (Button)findViewById(R.id.categoriesBtn);
    Button button3 = (Button)findViewById(R.id.highscoresBtn);
    Button button4 = (Button)findViewById(R.id.aboutBtn);

    button1.setOnClickListener(new OnClickListener() {   
        public void onClick(View arg0) {
            Intent intent1 = new Intent(MainMenu.this, QuestionView.class);
            startActivity(intent1);  
        }
    });
//more code...

Question.java

public class Question {
String a1;
String a2;
String a3;
String a4;
int correctAnswer;
String query;

public Question() {
}

public Question(String a1, String a2, String a3, String a4, int correctAnswer, String query) {
    this.a1 = a1;
    this.a2 = a2;
    this.a3 = a3;
    this.a4 = a4;
    this.correctAnswer = correctAnswer;
    this.query = query;        
}

public String getA1() { return a1; }
public String getA2() { return a2; }
public String getA3() { return a3; }
public String getA4() { return a4; }
public String getQuery() { return query; }
public int getCorrectAnswer() { return correctAnswer; }
  }

quick.java

public class Quiz {
ArrayList<Question> qList = new ArrayList<Question>();
public static ArrayList<Question> tenQs = new ArrayList<Question>(10);

public Quiz() {
    qList.add(new Question("A", "B", "C", "D", 3, "Question 1?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 2?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 3?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 4?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 5?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 6?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 7?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 8?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 9?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 10?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 11?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 12?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 13?"));
    qList.add(new Question("A", "B", "C", "D", 3, "Question 14?"));
}

public void getRandom10() {
    for(int i = 0; i < 10; i++) {
        Question x = qList.get((int) Math.floor((qList.size()+1)*Math.random()));
        if(tenQs.contains(x) == true) {
            i--;
        } else {
            tenQs.add(x);
        }
    }
}

public ArrayList<Question> getTenQs() { 
    return tenQs;
}
  }

---

任何帮助或意见都将不胜感激！提前谢谢。

您不需要调用

getRandom10（）

方法来初始化列表

编辑
此外，您在课堂

测验中使用了糟糕的设计：

tenQs
是您从
非静态
列表
qList
中填充数据的
静态
列表

另外，
tenQs
是
public
，可以通过class:
quick.tenQs
直接访问它。我想将其设置为
private
和
非静态
，并在construtor内部调用
getRandom10
，以确保
测验的正确初始化

将您的随机索引设置为：
代码：

Random r=new Random（）；
对于（int i=0；i<10；i++）{
问题x=qList.get（r.nextInt（qList.size（））；
添加（x）；
}

我明白了。如果将内部
用于
条件
for
循环中使用它。
将for循环条件更改为：

for(int i = 0; i < queries.size() ; i++)

for（int i=0；i

并确保在使用ArrayList之前初始化了
查询
ArrayList
qList.size（）+1=11，这样random将给出0到10之间的任何数字。。。所以，若数字是从0到9是可以的，但10会导致程序失败
 这是个例外。确保引用的数组项值已正确初始化，并且没有空值。找到它。我将getTenQs（）和getRandomTen（）组合成一个方法：public ArrayList getRandom10（）{for（int I=0；I内部
onCreate
，也如imran所述。什么不起作用？当我点击主菜单上的开始按钮时，一个新的活动出现了一个文本视图和4个按钮，但它们都是空字符串，所以什么也没有出现。它们应该从getQuery（）、getA1（）、getA2（）、getA3（）和getA4（）中填充，但显然有些东西不起作用。如果有帮助，请接受我的答案）
11-12 00:08:40.983: E/AndroidRuntime(4338): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.QuestionView}: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.os.Looper.loop(Looper.java:137)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread.main(ActivityThread.java:4745)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at java.lang.reflect.Method.invokeNative(Native Method)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at java.lang.reflect.Method.invoke(Method.java:511)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at dalvik.system.NativeStart.main(Native Method)
11-12 00:08:40.983: E/AndroidRuntime(4338): Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
11-12 00:08:40.983: E/AndroidRuntime(4338):     at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at java.util.ArrayList.get(ArrayList.java:304)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at com.example.test.QuestionView.onCreate(QuestionView.java:37)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.Activity.performCreate(Activity.java:5008)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
11-12 00:08:40.983: E/AndroidRuntime(4338):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)

Random r = new Random();
for(int i = 0; i < 10; i++) {
    Question x = qList.get(r.nextInt(qList.size()));
    tenQs.add(x);
}

for(int i = 0; i < queries.size() ; i++)